There are many different types of image capturing devices such as digital cameras, video cameras, or other photographic and/or image capturing equipment. These image capturing devices may use image sensors to capture images from a desired scene. For example, an image sensor may include an array of unit cells (i.e., a focal plane array) that receives light via a lens. The received light causes each unit cell in the array to accumulate an electric charge proportional to the light intensity at its location.
Focal Plane Arrays (FPAs) generally include a two-dimensional array of detector elements, or unit cells (i.e., pixels), organized in rows and columns. A circuit within each unit cell of the FPA accumulates charge corresponding to the incident flux radiation at a photodetector within the unit cell to generate an image of a scene or object within a field of view (FOV) of the FPA. For instance, most unit cell circuits detect optical radiation at a photodiode. The charge is accumulated in a capacitive element, which integrates the charge, and produces an integration voltage. The integration voltage corresponds to the intensity of the flux over a given time period referred to as the integration period (or integration interval, or integration time). The resulting voltage is conveyed by additional circuitry to an output of the FPA, which then may be used to construct the image of the scene that emitted the optical radiation. In some instances, such a voltage or charge can be digitized by circuitry of the FPA resulting in an array of digital values, at least one value for each unit cell of the FPA. Accordingly, in some instances FPAs may be used to convert a two-dimensional pattern of flux into a two-dimensional array of digital values, resulting in a digital image.
Each unit cell in an FPA generally corresponds to a picture element, or pixel, in the final image of the desired scene. A pixel is considered the smallest portion of a digital image. A digital image is generally made up of an array of pixels. Circuitry coupled to the image capturing device may perform post light capture processing steps to convert the accumulated charges from each unit cell into pixel information. This information may include the non-uniformity correction, color, saturation, brightness, or other information that a digital image storage or display format may require. Digital images may be stored in formats such as .JPG, .GIF, .TIFF, or any other suitable format. Digital images may be transferred in formats such as SMPTE-262, SMPTE-424, Camera Link, CoaXPress, Ethernet, HDMI, or any other suitable format.